Heat-developing apparatus for positive picture copiers



March 28, 1967 TQSHIO ISHIKAWA 3,311,040

HEAT-DEVELOPING APPARATUS FOR POSITIVE PICTURE COPIERS Filed Aug. 28, 1964 United States Patent 3,311,040 HEAT-DEVELOPING APPARATUS FOR POSITIVE PICTURE COPIERS Toshio Ishikawa, Kadoma, Osaka, Japan, assignor to Minolta Camera Kabushiki Kaisha, Osaka, Japan, a corporation of Japan 7 Filed Aug. 28, 1964, Ser. No. 392,892 Claims priority, application Japan, Apr. 8, 1964, 39/ 27,343 1 Claim. (CI. 95-94) The present invention relates to a novel and useful heat developing apparatus for positive picture copiers, which has a simple construction and is easily operable, and which enables to make homogeneous development over the entire picture surface.

Usually, the positive picture copier of the type referred to above is of such a construction that at the beginning of the copying operation, electric power may be used only for electric power to heat rollers, excepting a minute electric power for driving the copier, and that upon arriving at a certain temperature, the electric heating power may be automatically decreased by means of thermostat and relay, which maintains a certain temperature, and simultaneously controls a light source.

However in positive picture copiers according to the present invention, sensitized papers are used containing substances in emulsion which generate gases, such as ammonia, whereby development is performed by heating exposed, sensitized papers at a predetermined range of temperatures such as 150-200 C. to generate the gases, after which diazo-compounds effect a chemical reaction for producing colors. Thus, the present invention is contemplated to provide such a heat developing apparatus, the essential of which lies in a heat-developing apparatus for positive picture copiers, characterized in that a shrinking and heat-insulating, lagging material cylinder is fitted outside a rotary developing cylinder which in turn encloses therein a heat source and temperature controlling means, a heat-resistant sliding cloth inserted between the two cylinders, said sliding cloth being secured at one end to a hanging beam arranged opposite an opening of said lagging material cylinder, while the other end constituting a free end, and a clamping band is arranged around the outer periphery of said lagging material cylinder with one end being secured to thehanging beam and the other being secured to another hanging [beam through a tension spring. Thus, according to the present invention, in order that a sufficient amount of heat be supplied, the developing cylinder is provided with a heat source which can be maintained at a predetermined temperature range from 150 to 200 0., especially at approximately 160 C. with minimum electric current. The lagging material cylinder has a free inner diameter smaller than that of the developing cylinder and imparts self shrinking property, during the formation of the lamellar layers, and furthermore, as the cylinder is clamped uniformly with clamping belts from outside, the sensitized paper rotates, while being perfectly held in close contact with the developing cylinder, uniform development is advantageously attained over the entire surface.

In the following, the present invention is described in detail in connection with an embodiment of the invention. However, it is of course possible for those skilled in the art to make a number of appropriate improvements without departing from the spirit and range of the present invention. Similar parts are represented by similar symbols throughout figures of drawings, of which FIG. 1 is an oblique view of a positive picture copier equipped with the apparatus according to the present invention, With the cover portion being removed; and FIG. 2 is a cross-sectional view of FIG. 1.

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In the drawings, 1 denotes a rotary developing cylinder; 2 a lagging material cylinder; 3 an opening portion; 4 a notch; 5 a side plate; 6 and 7 hanging beams; 8 a heat resistant sliding cloth; 9 an inlet and 10 an outlet respectively. The outer periphery of developing cylinder 1 constitutes a slightly frictional disturbing surface and is adapted to rotate through a conventional driving mechanism from an appropriate driving source (not shown in the drawings), and any suitable bar-shaped ultra-red lamps or other heat sources (not illustrated) are provided in the cylinder. Furthermore, as shown in FIG. 2, the lagging material cylinder 2 is inserted on the outer periphery of developing cylinder 1, in order to keep the temperature of the cylindrical surface at the temperature necessary for development by said heat source, for instance, at 150 to 200C. and especially at approximately 160 C. The lagging material cylinder 2 comprises several lamellar layers of high heat insulation wound helically, such as glass fiber layers with the spaces between each layer being bonded with an appropriate high insulating adhesive. In this case, said lagging material cylinder is constructed smaller in diameter than the outer diameter of developing cylinder 1, and the inside of the lagging material cylinder is formed with notch 4 for easy attachment and removal.

As is illustrated in FIG. 1, the opening 3 is formed between the hanging beams 6 and 7 which are secured respectively to both plates 5, 5, and the heatresistant sliding cloth 8 formed of an extremely low frictional glass fiber cloth impregnated with plastic substance, such as trifluorresin or quatrofluorresi-n, is inserted with one end being secured to the beam 6, 'while the other end approaches, as a free end, to the opening portion 3. The opening portion is provided with a heat resistant cover 11 made of material similar to the lagging material cylinder 2 excepting the inlet 9 and outlet 10 for sensitized paper, which outlet is provided with a scraper 12. The periphery of the lagging material cylinder 2 is wound with clamping band 13 to impart a heat insulation and shrinking property; one end of the clamping band is secured to hanging beam 6 and the other end is connected to beam 7 so as to be always pulled by means of springs 14. Further, an automatic temperature control means (not illustrated), such as a thermostat or bimetal are provided in the developing device; both ends of the cylindrical 'bodies are arranged closely to the side plates 5, 5 and a heat insulating cover (not illustrated) is of course provided, Moreover, as shown in FIG. 2, the inlet 9 and outlet 10 are preferably provided with a pair of guide rollers oppositely engaging a driving roller 15 for driving sensitized paper.

. Thus in the present heat developing apparatus having above-mentioned construction, when the developing cylinder 1 reaches to an appropriate temperature by operation of the heat source, the exposed sensitized papers are charged from the inlet 9 through the guide and driving rollers. Since the rotating developing cylinder 1 is a frictional surface, while the heat resistant sliding cloth 8 permits easy sliding thereon, it follows that the sensitized paper inserted between both members is exposed to the predetermined temperature to 200 C. and is heatdeveloped, while rotating around the periphery in close contact with said developing cylindrical surface;.upon reaching the output 10, the developed paper is peeled off by scraper 12 and sent outwards through a pair of guide and driving rollers 15. In this case, even if the heat resistant sliding cloth 8 may be slightlyseparated from the cylinder 2 by extremely low friction, since one end of the sliding cloth is secured to the beam 6, it still retains its predetermined position corresponding to the lagging material cylinder 2; thus the free end of cloth 8 moves along the cylinder 2 during its rotation, without wrinkles occuring or being slackened as a whole.

What I claim is:

Heat-developing apparatus for positive picture copiers, characterized in that a shrinking and heat insulating, laggmg material cylinder is fitted outside a rotary developing cylinder which in turn encloses therein a heat source and temperature controlling means, a heat-resistant sliding cloth inserted between said two cylinders, said sliding cloth being secured at one end to a hanging beam ar- 1 ranged opposite an opening of said lagging material cylinder while its other end constitutes a free end, and a clamping band is arranged around the outer periphery 4 of said lagging material cylinder, one end of said band being secured to the hanging beam while its other end is secured through a tension spring to another hanging beam arranged opposite an opening of said lagging material cylinder.

References Cited by the Examiner UNITED STATES PATENTS 4/ 1963 Carrozza 95-94 4/1965 Steward 95-89 

